Research on Neurofeedback

For a detailed list of neurofeedback-related scholarly articles (with summaries) covering both its applications (therapeutic and non-therapeutic) and underlying brain mechanisms see the EEGInfo website. The relevant comprehensive scientific bibliography is provided also on the ISNR website

Here we only mention some of the most recent important research findings:

Neurofeedback training on sensorimotor rhythm in marmoset monkeys

Ingrid H.C.H.M. Philippens and Raymond A.P. Vanwersch

Neurofeedback research in a model closely related to humans is recommended to rule out placebo effects and unspecific factors bridging the gap between nonvalidated empirical and standardized controlled research. In this article telemetric sensorimotor rhythm (SMR; 11–14Hz) feedback training in the marmoset monkey is applied to examine the monkey’s capability to voluntary control their brain activity. Four monkeys, provided with two epidural bioelectric electrodes above the sensorimotor cortex, were trained with positive reinforcement on SMR measured by online analyses of 1.28 s electroencephalogram epochs in 30-min sessions. These monkeys learned within five sessions to increase their a activity. The first evidence of nonhuman primates having an operant control over the SMR is provided, an initial step for a much-needed scientific basis toneurofeedback. NeuroReport 21: 328 - 332 (2010). Article (with a video) on Newscientist »

Perceptual learning incepted by decoded fMRI neurofeedback without stimulus presentation

Kazuhisa Shibata, Takeo Watanabe, Yuka Sasaki and Mitsuo Kawato

It is controversial whether the adult primate early visual cortex is sufficiently plastic to cause visual perceptual learning (VPL). The controversy occurs partially because most VPL studies have examined correlations between behavioral and neural activity changes rather than cause-and-effect relationships. With an online-feedback method that uses decoded functional magnetic resonance imaging (fMRI) signals, we induced activity patterns only in early visual cortex corresponding to an orientation without stimulus presentation or participants’ awareness of what was to be learned. The induced activation caused VPL specific to the orientation. These results suggest that early visual areas are so plastic that mere inductions of activity patterns are sufficient to cause VPL. This technique can induce plasticity in a highly selective manner, potentially leading to powerful training and rehabilitative protocols. Science 334: 1413 - 1415 (2012).

Neurofeedback training of the upper alpha frequency band in EEG improves cognitive performance

Benedikt Zoefel, René J. Huster, Christoph S. Herrmann

In this study, the individually determined upper alpha frequency band in EEG (electroencephalogram) was investigated as a neurofeedback parameter. Fourteen subjects were trained on five sessions within 1 week by means of feedback dependent on the current upper alpha amplitude. On the first and fifth session, cognitive ability was tested by a mental rotation test. As a result, eleven of the fourteen subjects showed significant training success. Individually determined upper alpha was increased independently of other frequency bands. The enhancement of cognitive performance was significantly larger for the neurofeedback group than for a control group who did not receive feedback. Thus, enhanced cognitive control went along with an increased upper alpha amplitude that was found in the neurofeedback group only. Neuroimage 54: 1427 - 1431 (2011).

The overview of Neurofeedback mechanisms

Dr. Siegfried Othmer, Chief Scientist at The EEG Institute

The brain must be understood as an interacting network whose function is dependent on precise timing. The means by which the brain organizes and shapes its own timing must therefore be thoroughly understood. This involves first of all the "small-world" model of networks, which supports the high level of functional integration that we observe, as well as the hierarchical structure of regulation. It also involves the "time binding" model of sensory integration; the ensemble character of information in the brain; and the frequency-basis of organization of cortical activation and de-activation. Cortical and sub-cortical architecture must be re-evaluated in terms of its role in the maintenance of brain timing at the microscopic level, of ensembles at the intermediate level, and of networks at the global level.

Psychopathologies are then understood, in their physiological aspect, as failures of brain internal communication. Such failures may arise from inappropriate activation at certain sites, or from the inadequacies in communication within the networks, or from inappropriate coupling between different EEG frequencies. The latter has recently come to the fore through a general model of "thalamocortical dysrhythmias." This model complements, but does not contradict, neurochemical models of brain dysfunction. Neurochemical models are completely incapable on their own of yielding an understanding of the temporal dynamics of brain function, for which we must rely on bioelectrical models that can describe the time course of brain events. We must bring frequency-based analysis to bear.

Neurofeedback is then understood as an appeal to the mechanisms by which the brain maintains its own timing and frequency relationships. The brain must obey the laws that apply to any regulatory system. Moreover, it must assure its own stability entirely through self-regulatory means. By either operant conditioning or overt visual or electro-magnetic stimulation, the brain is arbitrarily moved out of its instantaneous state, thus invoking the brain’s own resources of control in the task of re-establishing regulation. Neurofeedback is therefore a gradual learning process in which the brain enhances its native skills of self-regulation. This holds true for all of those functions that are subject to regulation by timing, which includes all discrete events that involve synaptic information transport. The above is referred to as the "Regulatory Challenge" model of Neurofeedback.

We are able to deploy the technique of Neurofeedback successfully even before the underlying mechanisms of brain self-regulation are fully understood. This is because the brain can be viewed as a self-organizing nonlinear dynamical system. Through numerous internal feedback loops the brain is strongly constrained against large excursions in state space. When these do occur in the compromised brain, such deviations can be readily detected in the EEG and employed in negative feedback to the brain in order to further constrain its behavior. Over time, learning occurs and brain behavior improves. Neurofeedback can therefore be considered "behavior mod for the brain." Through thousands of cues per minute, based on increasingly sophisticated analysis of the EEG, the brain is shaped toward improved self-regulation. When remediation occurs systematically, we have our evidence for the validity of the initial assumption that the condition at issue was in fact mediated by frequency-based or timing-based disregulation.

It is in light of the above that claims of efficacy of Neurofeedback for a variety of conditions are to be understood. In some instances, such as Attention Deficit Disorder and PMS, we believe disregulation to be at the heart of the matter. The operative word in Attention Deficit Hyperactivity Disorder is Disorder. It follows that a self-regulation strategy should constitute a comprehensive remedy. Moreover, once re-regulation has been achieved, by whatever means, the defining aspects of the condition will no longer meet criteria to sustain a diagnosis.

In other conditions, however, disregulation merely accompanies a more structural deficit. This is the case for autism, for example, or traumatic brain injury, or Fetal Alcohol Syndrome. In these instances, the possible progress is constrained by organicity. The attempt at remediation seems, nevertheless, to be quite generally worthwhile. Finally, there are the degenerative conditions such as Parkinsonism and the dementias, where the EEG training may succeed in restoring and then maintaining function even in the face of continuing organic deterioration. In such cases, the training has to be kept up over time in order to maintain levels of function.

The benefit of Neurofeedback, whereas it has many explicit applications to psychopathologies and to neurological deficits, is deemed to be diagnostically non-specific. It addresses the broad functional disregulations that are part and parcel of all clinical syndromes in mental health, and accompany organic brain disorders as well. Neurofeedback can be seen as a generalization of what biofeedback has been traditionally concerned with. In the vernacular this has simply been called "relaxation," but in the scientific frame we are really concerned with self-regulation. By working with the EEG directly, the scope of our impact enlarges to all functions under the active management by the central nervous system.

This larger conception of EEG Neurofeedback addresses the entire activation-relaxation continuum of brain regulatory networks. It therefore impinges upon central and autonomic arousal, on attentional networks, on specific cognitive function, on working memory, and on other memory functions. It addresses the regulation of our moods and emotions; it covers motor control; and it modulates our sensitivity and reactivity to the sensory world. The training can moderate our fears as well as regulate our drives such as appetite, thrill-seeking, and drug-seeking. Most importantly, the training can confer essential stability on brain function, which heightens the threshold to such conditions as seizures, migraines, panic attacks, and bipolar excursions.

Neurofeedback may shortly be more generally recognized as being at the heart of Mind-Body Medicine, in that it utilizes volitional control in the training of sub-conscious brain processes that in turn regulate a variety of bodily functions. Whereas Neurofeedback has important medical implications, strictly speaking it is not intrinsically a medical procedure (although it becomes one when performed at the direction of an MD). It is simply a structured learning opportunity for the brain, one that can be supported by a variety of health or educational professionals. The technique is accessible to human beings of every age, provided there is sufficient sensory awareness at the brain level to respond to reinforcement.

As a non-medical procedure, Neurofeedback is likely to remain classified for some time as part of "Complementary or Alternative Medicine." This will remain true despite the fact that the concepts alluded to here will over time take a central place in our understanding of brain function. The understanding of the "Operating System of the Brain" will be one of the major preoccupations of the current century of neuroscience. How could that understanding not have therapeutic implications? In fact, those implications are already being realized in practice.

Even though our understanding may be limited, the reduction to practice is relatively straightforward. We simply have to know enough to cue the brain at any moment as to the direction in which improved performance lies, and that turns out not to be difficult at all in most instances. We simply monitor the brain's trajectory through state-space in the immediate past, and we reward the brain for moving to the more populated parts of state space, and discourage its migration toward the wings of the distribution. We reward the brain for moving to a state of higher complexity, or what is known as higher dimensionality. These regions of state space are intrinsically more stable. Remarkably, the brain learns from these cues and slowly changes its own habits. Life then reinforces the learned behavior so that the acquired skills of self-regulation are retained.